Gold recovery machine



y 1935. w. E. MENDENHALL 2,006,596

GOLD RECOVERY MACHINE Filed April 8, 1933 3 Sheets-Sheet 1 v o u u o o o o a a u a o a n o u a v q n a Q a a o a a o a a n o o o o w a u v o o .1

a a a u a o u o a a u a a a July 2, 1935. w. E. MENDENHALL GOLD RECOVERY MACHINE Filed April 8} 1933 3 Sheets-Sheet 2 July 2, 1935. w, E. MENDENHALL GOLD RECOVERY MACHINE Filed A rii 8, was 5 Sheets-Sheet 5' i/a/fe Patented July 2, 1935 STATES: PATENT oFF-IcE com) RECOVERY MACHINE walter 'Everett Mendenhall, Presc ttQAriz as j signor to Mendenhall Gold Concentrator C ompany, a corporation of Delaware Application April'8,1933, SerialNo.-665,0fi9 i if? l 2 Claims. .(oi,2o9'-- 437) This invention relates to a: gold recovery mah I. It is well known that'gold metal exists in the deposits along numerous river beds and valleys 5 and in the fine sand of placer mining deposits, in theform of fine particles, commonly known as gold flour, and that cannot be eifectively recovered by the usual placer mining-methods heretofore in use. In the-past, many futile efiorts have been made to recover this gold flour.

' In the Mendenhall Patent No. 1,509,681 there is disclosed an apparatus for recovering the gold flour from the sand or silt. The present'invem tion constitutes an improvement over the ap- 15" paratus therein shown. The improvement consists principally in the use of 'a-fabric or similar materialhavinginterstices or a retarding-action with respect to the gold flour upon the bottom of the trays and suitable deflecting means at the ends of the tray to-prevent the escape of gold flour during the agitation of the trays and cause such flour to be deflected back into the trays, and in the provision of a tray casing having a convex swinging movement into which water is sprayed to moisten the sand'in the trays." The water will wash the gold flour to the bottom of the tray dur ing the convex swinging movement thereof. --The invention comprises the novel structure and combination of parts hereinafterdescribed and-more particularly pointed out and defined in the appended claims. p

In the accompanying drawings which illustrate a preferred form of this invention and in which similarreference numerals refer to similar features in'the different views;

- Figure 1 is an elevational view of an apparatus involving this invention; 4

Figure 2' is a vertical sectional view through the apparatus taken upon the line II'II' of Fig. 1; Figure 3 is a fragmentary sectional'view of the trays-showing a slight modification thereof;

V Figure 4 is an enlarged sectional view taken substantially upon the line IV--IV of Fig. 2;

, Figure 5 is an enlarged fragmentary sectional view through a pair oftrays;

. Figure 6 is a sectional view of. the machine illustrating modified features of construction;

Figure '7 is a top plan view of a modified form ,1; of end discharge tray; ande g 5 Figure 8 isxa; top plan view of a center dischargetray. i

Figure 9 is a fragmentary sectional view taken upon the line IX-IX of Figure 7 looking in the direction of the arrows.

The illustrated embodiment of this invention consists of a supporting base ll upon which suitableuprights 2 are secured.- Theseuprights are suitably braced to form rigidsupportsw A casing 3 is suspended from the uprights by means of 5 adjustable links "4 which allow the casing'tobe swung to and fro or in a form of convex path.

A plurality of trays 5 and 5a in superposed relation arecarried by the casing 3 andsupported therein by means 'ofmetalmembers 6 at the bottom of the casing which'is otherwi'seopen. These metal members have'right angled ends 6a which are securedtothe sides'of the casing. The material passing from the trays falls upon a chute 1 which is attached to the uprights 2 as shown in Fig.1.-- The trays 5- which vare 'end discharge trays aresimilarin construction "and each consists of a square or rectangular frame 8 having acentral transverse partition 9 which is slotted as indicated at III for a purpose that will later appear. Spaced from the end frame members are transversefloorsupporting beams II and spaced from the partition9 are floor supporting beams l-zwhich are located at a lower elevation than, the beams II. The inwardly directed portions of these'beams are providedwith rabbets [3 which have curved deflector walls l l'for a purpose that will later appear, I j q I The floor H) of the'tray'is supported upon the beams II and l2 and extends'through.the slot [0. This floor consists of some'ma'terial whichhas interstices or which resists the travel of gold flour thereover, such as fabric. It has been discovered that canvas or duck has the proper characteristics and" for this, reason canvas has been illustrated asforming'the bottom of each tray. It will-"be noted-that the canvas floor of the tray" 5 consists of a medial depressed portion lia and upwardly sloping portions I51).

H The floor in the tray 511 is differently arranged than. the floor in the tray 5'. In the trayja the floor has a discharge gapat the center and iszhence formed inspaced sections; I6. It .will be noted that each section l6 which also con sists of canvas is fastened at its outer end be tween a pair of frame elements and 8bwhich form the end of the tray. Within the tray the floor sections I 6 are supported upon transverse beams I1 and I8. These beams have curved rab-- beted portions l3 similar to those above described and the beams I! are at a lower elevation than the'beams 18 with the result that each floor section has a leveldepressed portion lBa between receiving chute 29. The finer particles pass thru the machine and for this purpose a'fluid the beam I1 and the end of the tray. For it will be noted that the bottoms of rabbets in the beams I 1 are substantially in the same horizontal plane with the top of the frame element 8w. As the trays 5a discharge at the center, they may be termed center discharge trays.

In Figure 3 there is illustrated a pair of trays I9 and 20 in which the fabric bottoms 2| are of wavy or corrugated contour shown in exaggerated form. Such a corrugated contour will in some types of flake gold more readily retain the gold flour from movement toward the discharge point of the tray.

With reference to Figure 4 it will be noted that the upper tray 5 is adapted to discharge the coarse material thru the discharge gaps 22 between the beams II and the end frame mem-' bers. This material will fall upon the sections I6 of tray 50. therebeneath and the coarse particles and waste will be discharged thru the discharge gaps 23 and. descendupon the bottom of the next tray 5 which discharges the coarse material thru thedischarge gaps 22 between the beams II and the end frame-members. 'The discharged material will descend upon the bottom tray 5a and be discharged thru the final central gaps 23 and upon the discharge chute 1. Thus the trays 5 and 5a are alternately arranged so that as many such trays may be alternately used as desired; in the present case only four trays are shown, since practice has proven that a greater number are not usually required. More trays might, be used to advantage in recovery of unusually fine and flaky gold. s

In order that the coarse material will travel in the trays as above set forth, the casing 3 is adapted to be swung or oscillated by means of crank discs 24 connected by meansof links 25 to the casing 3. The crank discs 24 (only one of which is shown) are secured to the shaft 26 which may be driven by a pulley 21 and belt 28 from a. motor 29 on the base I.

Above'the trays, there is a sloping sieve or chute 29. having a; perforated bottom. I The sand containing the gold flour is deposited upon the thru the perforations the chute while the coarse particles will passdown the chute and not be discharged into the trays.

It is desirable to moisten the sand passing tank 30 is attached to the top of'the uprights 2. Suitable nozzles 3| attached to the bottom of the tank are adapted to spray a suitable fiuid, preferably water, upon the sand upon the chute 29;

During. the operation of the apparatus, which is apparent from the foregoing, the fine gold flour will be deposited'upon'the canvas bottoms of the tray as the coarse and lighter waste particles move upwardly upon the inclined bottoms of the tray duringthe oscillation of the casing. To effectively cause the best deposit of such gold flour, the bottoms of the tray should be of proper material to impede or prevent the gold flour from moving to the discharge ends of the bottoms of. the tray. A- fabric such as canvas having interstices in which the gold flour may become embedded and accumulate and that causes the gold fiour to adhere thereto and resists the movement of the gold flour thereover has in practice proven a commerical success.

During the oscillation of the casing, there is a tendency for the wet fiour to'be dashed over the ends of the bottoms of thetray, and to prevent this and at the sametime to the flour to be deflected back into the tray, the floors of the trays curve upwardly at the discharge aps as previously set forth. It will be appreciated that the continual spraying of the water as the trays swing to and fro will saturate the sand and wash the gold flour to the bottom, while the coarser material will be discharged. And due to the upward inclinations of the canvas bottoms of the'trays, the water will have a component of force acting against the bottoms and this will tend to force the gold flour into the canvas. This swinging movement of the trays in combination with the spraying of the sand with water is an important feature in the recovery of the gold flour.

After a sufficient quantity of this gold flour bearing material has been passed thru the appa- .ratus the sand collected in the trays will con- 7 tain large quantities of gold flour. The trays may be removed and the gold bearing sand removed and the metallic flour may then bebrushed'from the fabric bottoms. In time these fabric bottoms become saturated with metallic flour and may be removed and treated as the recovered metallic fiour.

In Figure 6, the parts are similar to the parts shown in Figures 1 and 2 except that the sand receiving chute which is designated by thereference 29a has been modified and theframes of the trays 5 and Saareslightly modified.

Describing first the modified chute 29a, it will be noted that it embodies a lower screen v32 spaced a short distance below the bottom of the main screen or chute 29a. Thelower ends of these screens incline downwardly as shown at 33 and transversely extending riiiles extend across the inclined portions to intercept nuggets of gold that may exist in thesand and that cannotpass thru the perforations in the screens. v

The end discharge tray 5 has been modified as shown in Figure 7. This modified form of tray which is designated by the reference 35 has the side frame members scarfed as indicated at 36 adjacent the partition 9, to prevent leakage between the trays. It will be noted that'these scarfs are bevelled and serve to deflect the water or saturated sand as it tends to pile up or 3.0-. cumulate at the corners where the scarfs exist. These scarfs direct the water upwardly and back into the tray so that it will not escape between the trays.

In Figure 8 there is shown a tray 31 similar to the tray So that has a center discharge and in which the side frame members are scarfed at their ends as indicated at 38. These scarfs are bevelled for preventing leakage between the trays as above explained. 7

It might be mentioned that the apparatus herein disclosed has gone into commercial use and is the first to succeedin a virtually complete recovery of fine and flaky gold and other valuable metallic substances from gravels, sands and soils.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, there fore, do not purposev limiting the patent granted hereon otherwise than necessitated'by the prior art.

I claim as my invention: a 1

1. In an apparatus of the 'classidescribed, a casing, means for oscillating said. casing in longitudinal directions, a plurality of trays in superposed relation inv sa d casing, said tray having sides with scarfs adjacent thecnd and. means.

for supplying fluid to said trays, said scarfs defleeting the fluid inwardly.

2. In a machine of the class described, a tray comprising a frame, a transverse member in said 5 tray in spaced relation from the end frame member, and having an arcuate rabbet, a second transverse member spaced inwardly from the first extending over said transverse members and in" contact with said arcuate rabbets for the purpose set forth.

WALTER EVERETT MENDENHALL. 

